Geotechnical engineers are responsible for ensuring the stability and integrity of structures built on or in the ground, including foundations, retaining walls, and earth dams.

The plasticity index of a soil is a measure of its ability to deform plastically without cracking. Soils with high plasticity indices generally have higher shear strength than soils with low plasticity indices.

The soil compaction test is used to determine the maximum dry density and optimum moisture content of a soil, which are important parameters for achieving proper compaction during construction.

Pile foundations are commonly used for structures built on soft or loose soils because they transfer the load of the structure to deeper, more stable soil layers.

Retaining walls are primarily used to support slopes or embankments, preventing them from collapsing or eroding.

Consolidation is the process by which soil settles and consolidates under load, resulting in a decrease in volume and an increase in density.

Sand is most susceptible to liquefaction during an earthquake because it can lose its strength and behave like a liquid when subjected to strong shaking.

Geotextiles are commonly used in geotechnical engineering to reinforce soil and prevent erosion, particularly in areas with steep slopes or unstable soil conditions.

The angle of internal friction is the angle at which a soil can withstand shear stress without failing. It is a measure of the soil's shear strength.

Clay is typically characterized by high plasticity and low permeability due to its fine-grained structure and high water content.

Slope stability analysis is conducted in geotechnical engineering to assess the stability of slopes and embankments, ensuring that they are safe from collapse or erosion.

Spread footings are commonly used for structures built on rock or hard soil because they can distribute the load of the structure evenly over a large area.

Capillary action is the process by which soil absorbs and retains water through the attraction of water molecules to the surface of soil particles.

Sand is typically characterized by low plasticity and high permeability due to its coarse-grained structure and low water content.

Geomembranes are commonly used in geotechnical engineering to prevent the migration of contaminants through soil, particularly in landfill and hazardous waste containment applications.